Matrix Zeros

Main.kt

/**
 * Given a 2D matrix, if an element is 0 set its entire row and column to 0. Do it in place
 *
 * Input:
 * [[1,1,1,1],
 * [1,1,1,0],
 * [1,1,1,1]]
 *
 * Output:
 * [[1,1,1,0],
 * [0,0,0,0],
 * [1,1,1,0]]
 */

fun main(){
    val matrix = arrayOf<IntArray>(
        intArrayOf(1, 1, 1, 1),
        intArrayOf(1, 1, 1, 0),
        intArrayOf(0, 1, 1, 1)
    )
    matrix.setMatrixZeros().asList().map { println(it.asList()) }
}
typealias Matrix = Array<IntArray>
fun Matrix.setMatrixZeros():Matrix{
    val guiltyRows = arrayListOf<Int>()
    this.forEachIndexed { index, ints ->
        if (ints.contains(0))
            guiltyRows.add(index)
    }

    var mutatedMatrix = this
    for (guiltyRow in guiltyRows){
        val guiltyColumn = this[guiltyRow].indexOf(0)
        mutatedMatrix = this.mapIndexed {index,it->
            if (index==guiltyRow) {
                IntArray(it.size){
                    0
                }
            }else{
                IntArray(it.size){mIndex->
                    if (mIndex==guiltyColumn)
                        0
                    else it[mIndex]
                }
            }
        }.toTypedArray()
    }
    return mutatedMatrix
}